Sampling a timing wheel, on whose surface markings are applied, and which is situated rotationally fixed on the relevant shaft, is known for detecting a specific position of a shaft, such as the crankshaft or the camshaft of an internal combustion engine. The sampling is performed using an inductive pickup or using a Hall sensor, for example, in which voltage pulses are induced by the passing markings, which are processed in a connected analysis circuit or a connected control unit, the speed of the shaft being calculated from the time intervals of the voltage pulses. These known apparatuses have the disadvantage that the angle marks must either be executed very exactly, so that the intervals between equivalent angle mark flanks are very precise, or the establishment of the speed may only be performed imprecisely.
Therefore, a method is discussed in International Patent Document WO 93/07497 for adapting mechanical tolerances of such a timing wheel, i.e., irregularities in the intervals of the angle marks. For this purpose, in overrun operation, in particular in overrun cut-off operation of an internal combustion engine of the motor vehicle, an adaptation is performed, in that in the case of recognized overrun operation, the second and the following time intervals to the first time interval, as recorded by the timing wheel, are set in relation to one another. It is disadvantageous therein that this method may only be used in conventional internal combustion engines, because overrun cut-off operation of the internal combustion engine is required for this purpose. Such operation occurs much more rarely in hybrid vehicles. It may thus take a relatively long time until an adaptation of this type may be performed; non-adapted states may occur in the intermediate time.
An object of the exemplary embodiments and/or exemplary methods of the present invention is to provide such an adaptation of mechanical tolerances of the timing wheel even outside overrun cut-off phases of the internal combustion engine.